Flight control systems of many diverse types have been widely utilized. They generally include a control surface and, in the case of a missile, the control surface is typically a fin. Generally, the control surface or fin is movable for purposes of flight control.
Generally speaking, it is recognized as being desirable to be able to lock the control surface in a selected position. The lock is typically designed to hold the control surface or fin at a null position from which it is released only on command from a controller. In the case of a missile, it is critical for the lock to disengage for proper deployment of the fin upon command.
Ideally, the lock would be resettable to permit the portion of a system that actuates the fin to undergo pre-launch testing. Such a resettable lock should be releasable in a low friction fashion and yet reengageable in a locked position to maintain the control surface or fin at the null position until launch. At that point, the controller should again be able to release the lock upon command to reposition the control surface or fin for flight.
Unfortunately, most locks for control surfaces have failed in numerous respects. For instance, some locks have been prone to sticking or otherwise failing to release upon command in a substantially frictionless fashion and nearly every lock has failed to even contemplate the possibility of a relatching system which would allow the operability of the overall flight control system to be tested during countdown while at the same time permitting automatic resetting without manual replacement of component-parts. Moreover, some locks have been prone to inadvertent unlatching due to vibration during normal operation.
Among the wide range of attempts to deal with these problems is that disclosed in Topliffe U.S. Pat. No. 4,373,688 which utilizes a latch pin for a canard drive mechanism which is withdrawn from a mating hole to begin deflecting a pair of deflectable canards once de-spinning reduces centrifugal force to a relatively low value.
Also, Geyer U.S. Pat. No. 3,102,437 has proposed an electromechanical actuator for positioning aerodynamic control surfaces which utilizes a releasable no-back means to permit rotation of a planet carrier for ultimate adjustment of output shafts.
Sadvary et al U.S. Pat. No. 4,575,025 proposes a fin deployment mechanism utilizing a pair of screw nuts, each of which is provided with a cam slot for receiving a cam follower mounted on the fin member to cause the fin to rotate through a given angle.
Watson U.S. Pat. No. 3,697,019 proposes a latch mechanism including a locking lug on the fin and a slot in the shroud to receive both the lug and a lug locking wedge to prevent movement of the fin in any direction from an erected position.
Liberman U.S. Pat. No. 4,210,298 proposes a plurality of solenoids operatively positioned relative to a rotary cam member and selectively activated to incline a torque producing lever-ball joint assembly to rotate wing panels in a desired direction.
Clearly, while many of these references relate in a general sense to locking systems for flight control surfaces, there has yet to be a reversible, low-friction locking means successively overcoming the above-stated problems.
The present invention is directed to overcoming the above-stated problems and accomplishing the stated objects.